遗传模拟退火算法对流水车间调度优化,目标为最小化最大流程时间,输出甘特图和收敛图,matlab代码如何编写
时间: 2024-01-24 22:02:45 浏览: 68
基于模拟退火遗传算法的车辆调度问题研究,用MATLAB语言加以实现
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以下是一个简单的Matlab代码示例,用于遗传模拟退火算法对流水车间调度问题进行优化:
```
% 流水车间调度问题的输入
num_jobs = 10; % 作业数量
num_machines = 3; % 机器数量
processing_time = randi([1,10], num_jobs, num_machines); % 加工时间矩阵
% 遗传模拟退火算法的参数设置
population_size = 50; % 种群大小
max_generations = 100; % 进化代数
mutation_rate = 0.02; % 变异率
temperature = 1000; % 初始温度
cooling_rate = 0.95; % 降温速率
% 初始化种群
population = randi([1,num_machines], population_size, num_jobs);
% 遗传算法进化
for i = 1:max_generations
% 计算适应度值
fitness = calculate_fitness(population, processing_time);
% 选择
parents = selection_tournament(population, fitness, 2);
% 交叉
offspring = crossover(parents);
% 变异
offspring_mutated = mutation(offspring, mutation_rate);
% 合并种群
population = [population; offspring_mutated];
% 保留最优个体
[~, idx] = sort(fitness, 'ascend');
population = population(idx(1:population_size), :);
% 模拟退火搜索
temperature = temperature * cooling_rate;
population = SA_search(population, processing_time, temperature);
end
% 输出结果
[best_fitness, best_idx] = min(calculate_fitness(population, processing_time));
best_schedule = population(best_idx, :);
plot_gantt_chart(best_schedule, processing_time);
% 计算适应度值函数
function fitness = calculate_fitness(population, processing_time)
num_jobs = size(population, 2);
end_time = zeros(size(population));
for i = 1:num_jobs
machine = population(:, i);
start_time = max(end_time(:, machine));
end_time(:, i) = start_time + processing_time(:, i);
end
fitness = max(end_time, [], 2);
end
% 选择函数
function parents = selection_tournament(population, fitness, k)
num_parents = size(population, 1);
parents = zeros(num_parents, size(population, 2));
for i = 1:num_parents
idx = randperm(num_parents, k);
[~, best_idx] = min(fitness(idx));
parents(i, :) = population(idx(best_idx), :);
end
end
% 交叉函数
function offspring = crossover(parents)
num_parents = size(parents, 1);
offspring = zeros(num_parents, size(parents, 2));
for i = 1:num_parents
parent1 = parents(i, :);
parent2 = parents(mod(i,num_parents)+1, :);
crossover_point = randi([1,size(parents,2)-1]);
offspring(i, :) = [parent1(1:crossover_point), parent2(crossover_point+1:end)];
end
end
% 变异函数
function offspring_mutated = mutation(offspring, mutation_rate)
num_offspring = size(offspring, 1);
offspring_mutated = offspring;
for i = 1:num_offspring
if rand() < mutation_rate
idx1 = randi([1,size(offspring,2)]);
idx2 = randi([1,size(offspring,2)]);
offspring_mutated(i, [idx1,idx2]) = offspring_mutated(i, [idx2,idx1]);
end
end
end
% 模拟退火搜索函数
function population = SA_search(population, processing_time, temperature)
num_jobs = size(population, 2);
end_time = zeros(size(population));
for i = 1:num_jobs
machine = population(:, i);
start_time = max(end_time(:, machine));
end_time(:, i) = start_time + processing_time(:, i);
end
fitness = max(end_time, [], 2);
for i = 1:size(population, 1)
new_population = population;
job = randi([1,num_jobs]);
machine1 = population(i, job);
machine2 = randi([1,size(population,2)]);
new_population(i, job) = machine2;
new_end_time = zeros(size(population));
for j = 1:num_jobs
machine = new_population(:, j);
start_time = max(new_end_time(:, machine));
new_end_time(:, j) = start_time + processing_time(:, j);
end
new_fitness = max(new_end_time, [], 2);
delta = new_fitness(i) - fitness(i);
if delta < 0 || rand() < exp(-delta/temperature)
population(i, job) = machine2;
end
end
end
% 绘制甘特图函数
function plot_gantt_chart(schedule, processing_time)
num_jobs = size(schedule, 2);
end_time = zeros(size(schedule));
for i = 1:num_jobs
machine = schedule(:, i);
start_time = max(end_time(:, machine));
end_time(:, i) = start_time + processing_time(:, i);
end
figure;
for i = 1:size(end_time, 1)
for j = 1:num_jobs
start_time = end_time(i, schedule(i,j)) - processing_time(schedule(i,j), j);
rectangle('Position', [start_time, i-0.5, processing_time(schedule(i,j), j), 1], 'FaceColor', 'b');
text(start_time + processing_time(schedule(i,j), j)/2, i, num2str(j), 'HorizontalAlignment', 'center', 'VerticalAlignment', 'middle');
end
end
xlim([0,max(end_time(:))]);
ylim([0,size(end_time,1)+0.5]);
xlabel('Time');
ylabel('Machine');
title('Gantt Chart');
end
```
这个示例代码将流水车间调度问题简化为了一个随机生成的加工时间矩阵,并使用了遗传算法和模拟退火算法进行优化。你可以根据你的具体问题进行修改和扩展。
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